﻿#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<ctype.h>
#include<string.h>

void test1()
{
	printf("%d\n", isdigit('6'));
	printf("%d\n", isspace(' '));
	printf("%d\n", islower('W'));
	printf("%c\n", toupper('a'));
	printf("%c\n", tolower('A'));
}

void test2()
{
	char arr[120] = { 0 };
	gets(arr);
	int i = 0;
	while (arr[i])//arr[i]不是0就继续循环
	{
		if (isupper(arr[i]))//是大写进入循环
		{
			arr[i] = tolower(arr[i]);//大写转化成小写
		}
		i++;
	}
	printf("%s\n", arr);
}

int main()
{
	test1();
	printf("\n");
	test2();
	return 0;
}
